What is the frequency of an x- ray if the wavelength is 4.5 e - 10m?

What are some properties of transverse waves?

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?

Aresistor with an unknown resistance is connected in parallel to a 9 ω resistor. when both resistors are connected in parallel to an emf source of 21 v, the current through the unknown resistor is measured with an ammeter to be 4 a. what is the resistance of the unknown resistor? answer in units of ω.